US9595486B2 - Metal oxide semiconductor structure - Google Patents

Abstract

A metal oxide semiconductor structure, the structure including: a substrate; a gate electrode, deposited on the substrate; a gate insulation layer, deposited over the gate electrode and the substrate; an IGZO layer, deposited on the gate insulation layer and functioning as a channel; a source electrode, deposited on the gate insulation layer and being at one side of the IGZO layer; a drain electrode, deposited on the gate insulation layer and being at another side of the IGZO layer; a first passivation layer, deposited over the source electrode, the IGZO layer, and the drain electrode; a second passivation layer, deposited over the first passivation layer; and an opaque resin layer, deposited over the source electrode, the second passivation layer, and the drain electrode.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a metal oxide semiconductor structure, especially to a metal oxide semiconductor structure having an opaque resin layer and at least two passivation layers.

Description of the Related Art

As IGZO (In—Ga—Zn—O) thin film transistor—utilizing IGZO for channel material—can be easily deposited on a glass substrate, many displays have utilized IGZO thin film transistors for controlling the gray levels of pixels. Please refer toFIG. 1, which illustrates a sectional view of a prior art thin film transistor structure. As illustrated inFIG. 1, the thinfilm transistor structure100 includes aglass substrate101, agate electrode102, agate insulation layer103, anIGZO layer104, asource electrode105a, adrain electrode105b, apassivation layer106, and aresin layer107.

In the structure, theglass substrate101 is used for carrying the other compositions of the thin film transistor structure.

Thegate electrode102, made of metal and deposited on theglass substrate101, is used for coupling to a gate driving signal.

Thegate insulation layer103, being an insulation layer deposited over thegate electrode102 and theglass substrate101, is used to insulate thegate electrode102 from theIGZO layer104, thesource electrode105a, and thedrain electrode105b.

The IGZOlayer104, being an N type semiconductor layer deposited on thegate insulation layer103, functions as a channel.

Thesource electrode105a, made of metal and deposited at one side of the IGZOlayer104, is used for coupling to a source driving signal.

Thedrain electrode105b, made of metal and deposited at another side of theIGZO layer104, is used for coupling to a pixel electrode.

Thepassivation layer106, made of a silicon compound and deposited over thesource electrode105a, theIGZO layer104, and thedrain electrode105b, is used for reducing leakage current of the channel.

Theresin layer107, being a transparent resin layer deposited over thesource electrode105a, thepassivation layer106, and thedrain electrode105b, is used to form a protection layer.

However, the thin film transistor structure specified above still suffers from photo leakage current effect. As illustrated inFIG. 2, the leakage current caused by a fourth light intensity—a strong light, with the thin film transistor being in a bias condition of V_gs=0V and V_ds=15V, is around 0.1 mA. In addition, the thin film transistor structure also suffers from degradation caused by invasion of moisture, oxygen, or hydrogen—whose amount increases with time, and the degradation will further increase the leakage current. As illustrated inFIG. 3, in same test condition, the leakage current measured on a first date (June 22) is around 10⁻¹³A, while the leakage current measured on a second date (July 15)—23 days later—is around 10⁻⁶A.

To conquer the flaws of the prior art thin film transistor structure mentioned above, the present invention proposes a novel metal oxide semiconductor structure, which utilizes a better shielding design for preventing light, moisture, and air from reaching the channel, thereby reducing the photo leakage current and avoiding the degradation of the channel.

SUMMARY OF THE INVENTION

One objective of the present invention is to disclose a metal oxide semiconductor structure, which can effectively prevent light, moisture, and air from reaching the channel, and thereby reduce the leakage current.

Another objective of the present invention is to disclose a method of making a metal oxide semiconductor structure, wherein the metal oxide semiconductor structure can effectively prevent light, moisture, and air from reaching the channel, and thereby reduce the leakage current.

To attain the foregoing objectives, a metal oxide semiconductor structure is proposed, the metal oxide semiconductor structure including a substrate, a gate electrode, a gate insulation layer, an IGZO layer, a source electrode, a drain electrode, a first passivation layer, a second passivation layer, and an opaque resin layer.

The substrate is used for carrying the other compositions of the metal oxide semiconductor structure.

The gate electrode, made of metal and deposited on the substrate, is used for coupling to a gate driving signal.

The gate insulation layer, being an insulation layer deposited over the gate electrode and the substrate, is used for insulating the gate electrode from the IGZO layer, the source electrode, and the drain electrode.

The IGZO layer, being an N type semiconductor layer deposited on the gate insulation layer, functions as a channel.

The source electrode, made of metal and deposited at one side of the IGZO layer, is used for coupling to a source driving signal.

The drain electrode, made of metal and deposited at another side of the IGZO layer, is used for coupling to a pixel electrode.

The first passivation layer, being a first silicon compound layer deposited over the source electrode, the IGZO layer, and the drain electrode, possesses excellent insulating property.

The second passivation layer, being a second silicon compound layer deposited over the first passivation layer, possesses excellent moisture-resistant and air-resistant properties.

The resin layer, being an opaque resin layer deposited over the source electrode, the second passivation layer, and the drain electrode, is used for forming a protection layer to prevent light, moisture, or dust from entering the structure.

To attain the foregoing objectives, a method of making a metal oxide semiconductor structure is proposed, the method including the following steps:

Step a: depositing a gate electrode on a substrate.

Step b: depositing a gate insulation layer over the gate electrode and the substrate.

Step c: depositing an IGZO layer on the gate insulation layer, wherein the IGZO layer functions as a channel.

Step d: depositing a source electrode at one side of the IGZO layer.

Step e: depositing a drain electrode at another side of the IGZO layer.

Step f: depositing a first passivation layer over the source electrode, the IGZO layer, and the drain electrode.

Step g: depositing a second passivation layer over the first passivation layer.

Step h: depositing an opaque resin layer over the source electrode, the second passivation layer, and the drain electrode.

To attain the foregoing objectives, another method of making a metal oxide semiconductor structure is proposed, the method including the following steps:

Step a: depositing a gate electrode on a substrate.

Step b: depositing a gate insulation layer over the gate electrode and the substrate.

Step c: depositing a source electrode at one side of the gate insulation layer.

Step d: depositing a drain electrode at another side of the gate insulation layer.

Step e: depositing an IGZO layer over the source electrode, the gate insulation layer, and the drain electrode, wherein the IGZO layer functions as a channel.

Step f: depositing a first passivation layer over the source electrode, the IGZO layer, and the drain electrode.

Step g: depositing a second passivation layer over the first passivation layer.

Step h: depositing an opaque resin layer over the source electrode, the second passivation layer, and the drain electrode.

To make it easier for our examiner to understand the objective of the invention, its structure, innovative features, and performance, we use preferred embodiments together with the accompanying drawings for the detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a sectional view of a prior art thin film transistor structure.

FIG. 2 illustrates photo leakage current effect of the thin film transistor structure inFIG. 1.

FIG. 3 illustrates degradation effect on leakage current of the thin film transistor structure inFIG. 1.

FIG. 4 illustrates a sectional view of a metal oxide semiconductor structure according to a preferred embodiment of the present invention.

FIG. 5 illustrates a sectional view of a metal oxide semiconductor structure according to another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in more detail hereinafter with reference to the accompanying drawings that show the preferred embodiments of the invention.

Please refer toFIG. 4, which illustrates a sectional view of a metal oxide semiconductor structure according to a preferred embodiment of the present invention. As illustrated in the figure, the metaloxide semiconductor structure200 includes asubstrate201, agate electrode202, agate insulation layer203, anIGZO layer204, asource electrode205a, adrain electrode205b, afirst passivation layer206, asecond passivation layer207, and anopaque resin layer208.

Thesubstrate201, of which the material includes glass or flexible plastics, is used for carrying the other compositions of the metal oxide semiconductor structure.

Thegate electrode202, made of metal—preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example—and deposited on thesubstrate201, is used for coupling to a gate driving signal.

Thegate insulation layer203, being an insulation layer deposited over thegate electrode202 and thesubstrate201, has an upward bending portion in the middle region. The insulation layer including silicon oxides or silicon nitrides, is used for insulating thegate electrode202 from theIGZO layer204, thesource electrode205a, and thedrain electrode205b.

TheIGZO layer204, being an N type semiconductor deposited on thegate insulation layer203 and functioning as a channel, has an upward bending portion in the middle region.

The source electrode205a, made of metal and deposited at one side of theIGZO layer204, has a stair-stepping outline and is used for coupling to a source driving signal. The metal is preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example.

Thedrain electrode205b, made of metal and deposited at another side of theIGZO layer204, has a stair-stepping outline and is used for coupling to a pixel electrode. The metal is preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example.

Thefirst passivation layer206, being a first silicon compound layer deposited over thesource electrode205a, theIGZO layer204, and thedrain electrode205b, has a downward bending portion in the middle region and possesses excellent insulating property. The first silicon compound layer preferably includes silicon oxides.

Thesecond passivation layer207, being a second silicon compound layer deposited over thefirst passivation layer206, has a downward bending portion in the middle region and possesses excellent moisture-resistant and air-resistant properties. The second silicon compound layer preferably includes silicon nitrides—due to the fact that silicon nitride, of which the density is higher than that of silicon oxide, can provide better moisture-resistant and air-resistant effects.

Theresin layer208, being an opaque resin layer—preferably in black color—deposited over thesource electrode205a, thesecond passivation layer207, and thedrain electrode205b, is used for forming a protection layer to prevent light, moisture, or dust from entering the structure.

Please refer toFIG. 5, which illustrates a sectional view of a metal oxide semiconductor structure according to another preferred embodiment of the present invention. As illustrated in the figure, the metaloxide semiconductor structure300 includes asubstrate301, agate electrode302, agate insulation layer303, asource electrode304a, adrain electrode304b, anIGZO layer305, afirst passivation layer306, asecond passivation layer307, and anopaque resin layer308.

Thesubstrate301, of which the material includes glass or flexible plastics, is used for carrying the other compositions of the metal oxide semiconductor structure.

Thegate electrode302, made of metal—preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example—and deposited on thesubstrate301, is used for coupling to a gate driving signal.

Thegate insulation layer303, being an insulation layer deposited over thegate electrode302 and thesubstrate301, has an upward bending portion in the middle region. The insulation layer including silicon oxides or silicon nitrides, is used for insulating thegate electrode302 from theIGZO layer305, thesource electrode304a, and thedrain electrode304b.

The source electrode304a, made of metal and deposited at one side of thegate insulation layer303, has a stair-stepping outline and is used for coupling to a source driving signal. The metal is preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example.

Thedrain electrode304b, made of metal and deposited at another side of thegate insulation layer303, has a stair-stepping outline and is used for coupling to a pixel electrode. The metal is preferably an opaque metal, implemented by Mo/Cr alloy or Al/Nd alloy, for example.

TheIGZO layer305, being an N type semiconductor deposited over thesource electrode304a, thegate insulation layer303, and thedrain electrode304b, and functioning as a channel, has a downward bending portion in the middle region.

Thefirst passivation layer306, being a first silicon compound layer deposited over thesource electrode304a, theIGZO layer305, and thedrain electrode304b, possesses excellent insulating property. The first silicon compound layer preferably includes silicon oxides.

Thesecond passivation layer307, being a second silicon compound layer deposited over thefirst passivation layer306, has a downward bending portion in the middle region and possesses excellent moisture-resistant and air-resistant properties. The second silicon compound layer preferably includes silicon nitrides—due to the fact that silicon nitride, of which the density is higher than that of silicon oxide, can provide better moisture-resistant and air-resistant effects.

Theresin layer308, being an opaque resin layer—preferably in black color—deposited over thesource electrode304a, thesecond passivation layer307, and thedrain electrode304b, is used for forming a protection layer to prevent light, moisture, or dust from entering the structure.

According to foregoing specification, the present invention further proposes a method of making a metal oxide semiconductor structure, including the steps of: depositing a gate electrode on a substrate (step a); depositing a gate insulation layer over the gate electrode and the substrate (step b); depositing an IGZO layer on the gate insulation layer, wherein the IGZO layer functions as a channel (step c); depositing a source electrode at one side of the IGZO layer (step d); depositing a drain electrode at another side of the IGZO layer (step e); depositing a first passivation layer over the source electrode, the IGZO layer, and the drain electrode (step f); depositing a second passivation layer over the first passivation layer (step g); and depositing an opaque resin layer over the source electrode, the second passivation layer, and the drain electrode (step h).

In step a, the material of the substrate includes glass or flexible plastics, and the deposited gate electrode is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step b, the deposited gate insulation layer has an upward bending portion in the middle region, and the insulation layer includes silicon oxides or silicon nitrides.

In step c, the deposited IGZO layer is an N type semiconductor layer, and has an upward bending portion in the middle region.

In step d, the deposited source electrode has a stair-stepping outline, and is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step e, the deposited drain electrode has a stair-stepping outline, and is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step f, the deposited first passivation layer has a downward bending portion in the middle region, and preferably includes silicon oxides.

In step g, the deposited second passivation layer has a downward bending portion in the middle region, and preferably includes silicon nitrides.

In step h, the deposited opaque resin layer is preferably in black color.

According to foregoing specification, the present invention proposes another method of making a metal oxide semiconductor structure, including the steps of: depositing a gate electrode on a substrate (step a); depositing a gate insulation layer over the gate electrode and the substrate (step b); depositing a source electrode at one side of the gate insulation layer (step c); depositing a drain electrode at another side of the gate insulation layer (step d); depositing an IGZO layer over the source electrode, the gate insulation layer, and the drain electrode, wherein the IGZO layer functions as a channel (step e); depositing a first passivation layer over the source electrode, the IGZO layer, and the drain electrode (step f); depositing a second passivation layer over the first passivation layer (step g); and depositing an opaque resin layer over the source electrode, the second passivation layer, and the drain electrode (step h).

In step a, the material of the substrate includes glass or flexible plastics, and the deposited gate electrode is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step b, the deposited gate insulation layer has an upward bending portion in the middle region, and the insulation layer includes silicon oxides or silicon nitrides.

In step c, the deposited source electrode has a stair-stepping outline, and is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step d, the deposited drain electrode has a stair-stepping outline, and is preferably made of an opaque metal—Mo/Cr alloy or Al/Nd alloy, for example.

In step e, the deposited IGZO layer is an N type semiconductor layer, and has a downward bending portion in the middle region.

In step f, the deposited first passivation layer preferably includes silicon oxides.

In step g, the deposited second passivation layer preferably includes silicon nitrides.

In step h, the deposited opaque resin layer is preferably in black color.

Due to the novel designs elaborated above, the present invention has the following advantages:

1. The opaque resin layer can prevent light from reaching the IGZO layer, thereby reducing photo leakage current.

2. The first passivation layer has excellent electrical insulating property, which can contribute to reducing leakage current of the channel.

3. The second passivation layer has excellent moisture-resistant and air-resistant properties, which can contribute to preventing the degradation of the IGZO layer.

In conclusion, the metal oxide semiconductor structure of the present invention can provide multi protections including light shielding, moisture resisting, and air resisting, for reducing leakage current, so the present invention does conquer the flaws of the prior art thin film transistors.

While the invention has been described by way of example and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.

In summation of the above description, the present invention herein enhances the performance than the conventional structure and further complies with the patent application requirements and is submitted to the Patent and Trademark Office for review and granting of the commensurate patent rights.

Claims (19)

What is claimed is:

1. A metal oxide semiconductor structure, comprising:

a substrate;

a gate electrode deposited on said substrate, for coupling to a gate driving signal;

a gate insulation layer deposited over the gate electrode;

a metal oxide layer deposited on the gate insulation layer;

a source electrode deposited at one side of the metal oxide layer, for coupling to a source driving signal;

a drain electrode deposited at another side of the metal oxide layer, for coupling to a pixel electrode;

a first passivation layer, being a first silicon compound layer deposited over the source electrode, the metal oxide layer, and the drain electrode;

a second passivation layer, being a second silicon compound layer different from the first silicon compound layer and deposited over the first passivation layer; and

an opaque resin layer deposited over and directly connected to the source electrode, the second passivation layer, and said drain electrode.

2. The metal oxide semiconductor structure asclaim 1, wherein said gate insulation layer has an upward bending portion and comprises a silicon compound selected from a group consisting of a silicon oxide and a silicon nitride.

3. The metal oxide semiconductor structure asclaim 1, wherein said source electrode has a stair-stepping outline and comprises an alloy selected from a group consisting of Mo/Cr alloy and Al/Nd alloy.

4. The metal oxide semiconductor structure asclaim 1, wherein said drain electrode has a stair-stepping outline and comprises an alloy selected from a group consisting of Mo/Cr alloy and Al/Nd alloy.

5. The metal oxide semiconductor structure asclaim 1, wherein said first passivation layer has a downward bending portion and said first silicon compound layer comprises a silicon oxide.

6. The metal oxide semiconductor structure asclaim 1, wherein said second passivation layer has a downward bending portion and said second silicon compound layer comprises a silicon nitride.

7. The metal oxide semiconductor structure asclaim 1, wherein said opaque resin layer is in black color.

8. A metal oxide semiconductor structure, comprising:

a substrate;

a gate electrode deposited on said substrate, for coupling to a gate driving signal;

a gate insulation layer deposited over said gate electrode;

an IGZO layer, being an In—Ga—Zn—O layer deposited on said gate insulation layer, for functioning as a channel;

a source electrode deposited at one side of said IGZO layer, for coupling to a source driving signal;

a drain electrode, deposited at another side of said IGZO layer, for coupling to a pixel electrode;

a first passivation layer deposited over said source electrode, said IGZO layer, and said drain electrode;

a second passivation layer, being a single continuous layer, deposited over an upper surface of said first passivation layer; and

a resin layer, said resin layer being an opaque resin layer deposited over and directly connected to said source electrode, said first passivation layer, said second passivation layer, and said drain electrode.

9. The metal oxide semiconductor structure asclaim 8, wherein said IGZO layer has an upward bending portion.

10. The metal oxide semiconductor structure asclaim 8, wherein said first passivation layer is a silicon oxide layer and has a downward bending portion.

11. The metal oxide semiconductor structure asclaim 8, wherein said second passivation layer is a silicon nitride layer and has a downward bending portion.

12. The metal oxide semiconductor structure asclaim 8, wherein said resin layer is in black color.

13. A metal oxide semiconductor structure, comprising:

a substrate;

a gate electrode deposited on said substrate, for coupling to a gate driving signal;

a gate insulation layer deposited over said gate electrode and said substrate;

an IGZO layer, being an In—Ga—Zn—O layer deposited on said gate insulation layer;

a source electrode deposited at one side of said IGZO layer, for coupling to a source driving signal;

a drain electrode deposited at another side of said IGZO layer, for coupling to a pixel electrode;

a first passivation layer deposited over said source electrode, said IGZO layer, and said drain electrode;

a second passivation layer deposited over an upper surface of said first passivation layer, said first passivation layer and said second passivation layer are different compound layer; and

a resin layer deposited over and directly connected to said source electrode, said first passivation layer, said second passivation layer, and said drain electrode.

14. The metal oxide semiconductor structure asclaim 13, wherein said substrate comprises a material selected from a group consisting of glass and flexible plastics.

15. The metal oxide semiconductor structure asclaim 13, wherein said gate insulation layer has an upward bending portion and comprises a silicon compound selected from a group consisting of a silicon oxide and a silicon nitride.

16. The metal oxide semiconductor structure asclaim 13, wherein said IGZO layer has an upward bending portion.

17. The metal oxide semiconductor structure asclaim 13, wherein said first passivation layer is a silicon oxide layer and has a downward bending portion.

18. The metal oxide semiconductor structure asclaim 13, wherein said second passivation layer is a silicon nitride layer and has a downward bending portion.

19. The metal oxide semiconductor structure asclaim 13, wherein said resin layer is in black color.

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